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Dive into the research topics where Gulderen Yanikkaya Demirel is active.

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Featured researches published by Gulderen Yanikkaya Demirel.


Cytokine | 2012

Cytokine profiles in serum of patients with oral lichen planus.

Filiz Namdar Pekiner; Gulderen Yanikkaya Demirel; Mehmet Oğuz Borahan; Semih Özbayrak

OBJECTIVE Oral lichen planus (OLP) is a chronic inflammatory disorder of oral mucosa, which represents T-cell-mediated autoimmune diseases. The inflammatory response in OLP is characterized by the accumulation and expansion of T-helper 1 (Th1) lymphocytes. Several lines of evidence have suggested that a complex cytokine network plays an important role in the exacerbation and perpetuation of OLP. The aim of this study was to evaluate Th1 and T-helper 2 (Th2) cytokine profile in serum of patients with OLP in comparison to healthy controls. METHODS Thirty patients with OLP, and 30 healthy controls participated in the study. Tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-5 and IL-10 levels have been measured in flow cytometry by bead based cytokine measurement. RESULTS Although no statistical differences were observed in the serum levels of TNF-α, IFN-γ, IL-5 and IL-4 between OLP patients and controls (p>0.05), there were statistically significant differences in the serum levels of IL-2 and IL-10 (p<0.05 and p<0.01, respectively). A significantly decreased tendency towards the levels of IL-2 were observed in OLP patients when compared to controls (p<0.05), and the mean level of IL-10 in serum increased remarkably in the OLP patients than those in the controls (p<0.01). CONCLUSIONS The finding of higher serum levels of IL-10 in patients in presence of low serum IL-2 levels, shows us that there is a dominance of Th2 response. This makes us think that there is a change in Th1/Th2 balance. Dominance of the Th2 response may indicate that OLP could be a result of a delayed type hypersensitivity.


Journal of Oral Pathology & Medicine | 2009

Burning mouth syndrome and saliva: detection of salivary trace elements and cytokines.

Filiz Namdar Pekiner; Birsay Gümrü; Gulderen Yanikkaya Demirel; Semih Özbayrak

BACKGROUND Burning mouth syndrome (BMS) is considered a syndrome with an unknown cause. Roles of various trace elements and cytokines in saliva have been implicated in the development of BMS. The aim of the present study was to compare the levels of salivary trace elements [magnesium (Mg), zinc (Zn), copper (Cu)] and interleukin (IL)-2 and IL-6, and to search for a correlation between depression/anxiety and salivary trace elements and cytokines in BMS patients and controls. METHODS Thirty patients with BMS and 30 matched healthy controls participated in the study. Unstimulated saliva was collected from participants and salivary flow rates were determined. Mg, Zn and Cu levels were determined by atomic absorbance spectrophotometry. Cytokine immunoassay kits were used to determine the concentration of IL-2 and IL-6 in the whole saliva samples. Anxiety and depression were analyzed by means of the Speilberger State-Trait Anxiety Inventory (SAI-TAI) and Zung Self-Rating Depression Scale. RESULTS Although subjects in the control group had significantly higher mean levels for Mg compared with BMS patients (P < 0.01), no statistically significant differences were observed in relation to Zn and Cu levels between the two groups (P < 0.001). There were no statistically significant differences in IL-2 and IL-6 levels of BMS and control groups, but subjects in BMS group had slightly, not significantly, higher mean levels for IL-6 compared with controls. Subjects in BMS group had significantly higher mean values for TAI compared with controls (P < 0.05). There were no statistically significant differences in relation to salivary levels of Mg, Zn, Cu, IL-2, IL-6 and depression/anxiety between BMS and control groups. CONCLUSIONS The results of our study indicate that Mg levels could have an impact on symptoms of BMS and further studies are necessary to determine the importance of cytokines in the pathogenesis of BMS.


Journal of Oral Pathology & Medicine | 2008

Serum cytokine and T regulatory cell levels in patients with burning mouth syndrome

Filiz Namdar Pekiner; Gulderen Yanikkaya Demirel; Birsay Gümrü; Semih Özbayrak

BACKGROUND Burning mouth syndrome is a disorder usually associated with an unexplained, prolonged sensation of burning inside the oral cavity. Although the etiology is unknown, neural and psychologic factors and cytokines may be implicated in the pathogenesis of burning mouth syndrome. The aim of this study was to investigate the relationship between serum cytokine and T regulatory cell levels in patients with burning mouth syndrome with regard to depression and anxiety. METHODS Thirty patients with burning mouth syndrome and 30 matched controls participated in the study. Serum cytokine levels were measured with cytometric bead array and T regulatory cells were defined as CD4(+)CD25(+)Foxp-3(+) cells by flow cytometry. The level of anxiety and depression were analyzed by means of the Speilberger State-Trait Anxiety Inventory and Zung Self-Rating Depression Scale. Visual analogue scale was used in the quantification of burning levels of patients. RESULTS Serum IL-2 and TNF-alpha levels were significantly decreased in patients with burning mouth syndrome compared with controls [mean 16.79 +/- 8.70 vs. 37.73 +/- 41.05 pg / ml (P < 0.05) and mean 39.09 +/- 29.40 vs. 70.83 +/- 42.44 pg / ml (P < 0.01) respectively]. CONCLUSIONS IL-2 and TNF-alpha might play a role in burning mouth syndrome. Burning mouth syndrome may occur as a sign of predisposition to autoimmunity. Presence of low levels of CD28(+) supports the provision that BMS might be a pre-autoimmune disease.


Cytometry Part B-clinical Cytometry | 2013

Accreditation of flow cytometry in Europe

Ulrich Sack; David Barnett; Gulderen Yanikkaya Demirel; Chantal Fossat; Stephan Fricke; Nikolitsa Kafassi; Thomas Nebe; Katherina Psarra; Jörg Steinmann; Claude Lambert

ISO 15189 has been introduced to enable any clinical laboratory, irrespective of geographic location, to be accredited against internationally recognized standards and therefore facilitate direct international comparison of laboratories. Together with increasing use of ISO 15189 for standardization and competition purposes, often triggered by demands of patients and clinicians, clinical flow cytometry laboratories are becoming increasingly challenged to introduce compliant quality management systems. Whilst in most countries, ISO 15189 accreditation is not yet compulsory, there is increasing evidence to suggest that the implementation of this standard is growing. As a result, the European Society of Clinical Cell Analysis (ESCCA) has analysed the impact of accreditation in clinical flow cytometry laboratories. It found, through a discussion forum, that staff qualification, adaptation of multicolour antibody panels, and implementation of a comprehensive quality system (including quality assessment) have been identified as major challenges.


Journal of Oral Pathology & Medicine | 2012

Interleukin-2, interleukin-6 and T regulatory cells in peripheral blood of patients with Behçet's disease and recurrent aphthous ulcerations.

Filiz Namdar Pekiner; Emre Aytugar; Gulderen Yanikkaya Demirel; Mehmet Oğuz Borahan

BACKGROUND One of the factors involved in the pathogenesis of Behçet disease (BD) and recurrent aphthous ulcerations (RAU) is a cell-mediated immune response in which several cytokines (interleukin-2, interleukin-6) and T regulatory cell (T reg cell) population seem to play a major role. The aim of this study was to measured the interleukin-2 (IL-2), interleukin-6 (IL-6) levels and analysis of CD4(+) CD25(+) Foxp-3(+) Treg cells in peripheral blood from patients with BD and RAU. In addition; we also analysed peripheral blood from healthy subjects for comparison. METHODS Thirty patients (15 men and 15 women) with BD, 30 patients (12 men and 18 women) with RAU and 15 healthy control subjects (nine men and six women) participated in the study. Analysis of CD4(+) CD25(+) Foxp-3(+) Treg cells, IL-2 and IL-6 levels have been measured in flow cytometry. RESULTS No statistical differences were observed in the serum levels of IL-2 and IL-6 between BD and RAU patients, and healthy subjects. Although there were no statistical differences in the number of CD4(+) CD25(+) Foxp-3(+) cells between groups, there were statistically significant differences in the number of CD4(+) CD25(bright) Treg cells. CD4(+) CD25(bright) Treg cells were significantly increased in BD and RAU patients compared to healthy subjects. Statistical analysis revealed no difference according to the number of CD4(+) CD25(bright) cells between BD and RAU patients. CONCLUSIONS These results indicate that CD4(+) CD25(bright) T regulatory cells may be contributing factor in the pathogenesis of BD and RAU.


Basic & Clinical Pharmacology & Toxicology | 2016

Agmatine Reverses Sub-chronic Stress induced Nod-like Receptor Protein 3 (NLRP3) Activation and Cytokine Response in Rats.

Ceren Sahin; Ozgur Albayrak; Tuğba F. Akdeniz; Zeynep Akbulut; Gulderen Yanikkaya Demirel; Feyza Aricioglu

The activation of Nod‐like receptor protein 3 (NLRP3) has lately been implicated in stress and depression as an initiator mechanism required for the production of interleukin (IL)‐1β and IL‐18. Agmatine, an endogenous polyamine widely distributed in mammalian brain, is a novel neurotransmitter/neuromodulator, with antistress, anxiolytic and antidepressant‐like effects. In this study, we examined the effect of exogenously administered agmatine on NLRP3 inflammasome pathway/cytokine responses in rats exposed to restraint stress for 7 days. The rats were divided into three groups: stress, stress+agmatine (40 mg/kg; i.p.) and control groups. Agmatine significantly down‐regulated the gene expressions of all stress‐induced NLRP3 inflammasome components (NLRP3, NF‐κB, PYCARD, caspase‐1, IL‐1β and IL‐18) in the hippocampus and prefrontal cortex (PFC) and reduced pro‐inflammatory cytokine levels not only in both brain regions, but also in serum. Stress‐reduced levels of IL‐4 and IL‐10, two major anti‐inflammatory cytokines, were restored back to normal by agmatine treatment in the PFC. The findings of the present study suggest that stress‐activated NLRP3 inflammasome and cytokine responses are reversed by an acute administration of agmatine. Whether antidepressant‐like effect of agmatine can somehow, at least partially, be mediated by the inhibition of NLRP3 inflammasome cascade and relevant inflammatory responses requires further studies in animal models of depression.


Cytometry Part B-clinical Cytometry | 2017

Monocytes and macrophages in flow: An ESCCA initiative on advanced analyses of monocyte lineage using flow cytometry.

Claude Lambert; Frank Preijers; Gulderen Yanikkaya Demirel; Ulrich Sack

In April 2013, a symposium was organized to highlight different aspects of differentiation and activation of the monocyte‐macrophage lineage as analyzed on the flow cytometer. Characterization of this lineage requires knowledge of the maturation process from their progenitors that are present in bone marrow up to the mature monocytic cells in peripheral blood, because each monocytic lineage cell with an aberrant phenotype refers to the corresponding maturation stage. A standardized quantitative analysis will facilitate the monitoring of the pathological processes and the clinical features, such as the outcome of treatment. However, changes in marker expression by variation in intensity, asynchronism, and lineage infidelity must be considered. The dynamics of normal marker expressions in early differentiation stages, e.g. molecules like HLA II, CD64 or CD14, give rise to a hypothesis on their possible role in monocyte ontogeny. Besides their usual role in tissue homeostasis, mature macrophages may also play a similar role in hematopoiesis. This meeting highlighted the large potential of flow cytometric tools available for monitoring of all these aspects in the monocytic and macrophage cell lineage.


Medical Principles and Practice | 2013

HLA-A, B (Class I) and HLA-DR, DQ (Class II) antigens in Turkish patients with recurrent aphthous ulceration and Behçet's disease.

Filiz Namdar Pekiner; Emre Aytugar; Gulderen Yanikkaya Demirel; M. Oğuz Borahan

Objective: The aims of the present study were to typify the human leukocyte antigen system (HLA)-A, B (class I) and HLA-DR, DQ (class II) antigens and to assess the frequency of the presence of these antigens in the Turkish population with recurrent aphthous ulceration (RAU) and Behçets disease (BD) compared to healthy subjects. Subjects and Methods: Thirty patients with RAU, 30 with BD, and 15 healthy subjects were included in the study. HLA typing was performed by serology with commercial kits for HLA class I and II (One Lambda, Canoga Park, Calif., USA). Results: The HLA-A23 frequency was 26.7% in the RAU patients, which was significantly higher than the 3.3% frequency in the patients with BD (p < 0.05). The HLA-A24 frequency was 33.3% in the RAU patient group, which was significantly higher (p < 0.05) than the frequency in the healthy subjects (6.7%). Significantly higher frequencies (46.7%) of HLA-A30 were found in the healthy subjects compared to the BD (13.3%) and RAU (3.3%) patients (p < 0.05 and p < 0.01, respectively). A higher frequency of HLA-B13 was observed in the RAU (23.3%) patients compared to the BD (0%) patients (p < 0.01). A decrease was observed in HLA-DR10 and HLA-DR17 in the RAU patients (p < 0.05), while a higher frequency of HLA-DR10 was observed in the BD patients compared to the RAU patients (p < 0.01). Conclusions: These results showed that RAU and BD were not in the same spectrum and the involvement of other genetic and/or environmental factors might be responsible for the development of these diseases and/or disease progression.


Kidney & Blood Pressure Research | 2014

Effects of Paricalcitol and Aliskiren Combination Therapy on Experimental Diabetic Nephropathy Model in Rats

Zehra Eren; Mehmet Yalçın Günal; Elif Arı Bakır; Jale Çoban; Berrak Caglayan; Nur Ekimci; Sinem Ethemoglu; Ozgur Albayrak; Tuba Akdeniz; Gulderen Yanikkaya Demirel; Ertugrul Kilic; Gulcin Kantarci

Background/Aims: The aim of the present study was to investigate the effect of combination of aliskiren with paricalcitol on experimental diabetic nephropathy (DN) model in rats. Methods: Forty male Sprague Dawley rats were divided into 5 groups of 8 rats each, namely the control (Group C), diabetes (Group D), aliskiren (Group A), paricalcitol (Group P), and aliskiren plus paricalcitol (Group A+P) groups. Aliskiren was given by oral-gavage at a dose of 50 mg/kg/day once daily for 12 weeks. Paricalcitol was given by intraperitoneally at a dose of 0,4 µg/kg/three day of week for 12 weeks. Renal function parameters, oxidative stress biomarkers, mRNA expression of renin-angiotensin system parameters and kidney histology were determined. Results: Group A+P had lower mean albümin-to-creatinine ratio (ACR) (p=0.004) as well as higher creatinine clearance (CCr) (p<0.005) than the diabetic rats (Group D). Combination therapy significantly increased CCr (Group A+P vs Group A, p<0.005; Group A+P vs Group P, p=0.022) and reduced ACR (Group A+P vs Group A, p=0.018; Group A+P vs Group P, p<0.005) when compared to monotherapy. Serum malondialdehyde levels were significantly lower (p=0.004); glutathion levels (p=0.003), glutathion peroxidase (p=0.004) and superoxide dismutase (p<0.005) activities were significantly higher in group A+P than in group D. The mean scores of mRNA expression of renin (p<0.005), angiotensin II (p=0.012) and angiotensin type 1 receptor (p=0.018) in group A+P were significantly lower. Although combination therapy showed no additional effect on oxidative system, renin-angiotensin system and renal histology, aliskiren plus paricalcitol significantly decreased interstitial fibrosis volume when compared to monotherapy (Group A+P vs Group A, p<0.005; Group A+P vs Group P, p=0.002). Conclusion: Our data seem to suggest a potential role of aliskiren plus paricalcitol acting synergystically for reducing the progression of diabetic nephropathy in an experimental rat model.


Journal of Oral Pathology & Medicine | 2012

Evaluation of cytotoxic T‐cell activation, chemokine receptors, and adhesion molecules in blood and serum in patients with oral lichen planus

Filiz Namdar Pekiner; Gulderen Yanikkaya Demirel; Mehmet Oğuz Borahan; Semih Özbayrak

BACKGROUND Our purpose is to study cytotoxic T-cell activation (through evaluation of CD8+CD40+ and CD8+CD154+ cells), chemokine receptors (through evaluation of CD8+CD184+ and CD8+CD195+ cells), and adhesion molecules (through evaluation of CD8+CD152+ cells) which play a part in cell activation in blood and serum samples of patients with OLP and then to compare them with healthy controls. METHODS Thirty patients with OLP, and 30 matched healthy controls participated. The mean ages of OLP patients and controls were 51,10 ± 12,25 and 48,09 ± 11,92, respectively. Percentage of apoptotic cells, granzyme-B+, CD8+, CD8+CD40+, CD8+CD152+ (CTLA-4), CD8+CD154+(CD40L), CD8+CD184+(CXCR-4) and CD8+CD195+(CCR-5) were detected by immunophenotyping on flow cytometry. Apoptosis measurements were accomplished with Annexin V/Propidium Iodide kit. RESULTS A higher percentage of CD8+CD154+ and granzyme-B+ and a lower percentage of CD8+, CD8+CD184+ and apoptotic cells were found in OLP patients than in controls. No statistical differences were observed in the percentages of the other markers between groups. CONCLUSIONS It is observed that because of increase in granzyme B+ and CD154 which is the activation marker, CD8+ cells present efforts to sustain their activity even though decrease in their cell number. Lower levels of CD8+CD184+ cells in OLP than control is evaluated as a factor that makes OLP to be localised in our study. In addition, our findings lead us to think that there may be some changes in apoptosis pathways of the cells. But this needs to be clarified by further studies exploring the mechanisms of the apoptosis in OLP patients.

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